Janey and her brother are having fun at the beach. It’s a warm, sunny day, and the sand feels hot on their bare feet. They take a dip in the water whenever they want to cool off because the water feels much cooler than the sand. Why does the sand—but not the water—get hot in the sun? The answer has to do with specific heat.

Be Specific

Specific heat is a measure of how much energy it takes to raise the temperature of a substance. It is the amount of energy (in joules) needed to raise the temperature of 1 gram of the substance by 1 °C. Specific heat is a property that is specific to a given type of matter. That’s why it’s called specific.

Variation in Specific Heat

The Tablebelow compares the specific heat of four different substances. Metals such as iron have low specific heat. It doesn’t take much energy to raise their temperature. That’s why a metal spoon heats up quickly when placed in a cup of hot coffee. Sand also has a relatively low specific heat. Water, on the other hand, has a very high specific heat. It takes a lot more energy to increase the temperature of water than sand. This explains why the sand on a beach gets hot while the water stays cool. Differences in the specific heat of water and land even affect climate. To learn how, watch the video at this URL: http://www.youtube.com/watch?v=dkBStF2Rnu4

Q: Metal cooking pots and pans often have wooden handles. Can you explain why?

A: Wood has a higher specific heat than metal, so it takes more energy to heat a wooden handle than a metal handle. As a result, a wooden handle would heat up more slowly and be less likely to burn your hand when you touch it.

Summary

Specific heat is a measure of how much energy it takes to raise the temperature of a substance. It is the amount of energy (in joules) needed to raise the temperature of 1 gram of the substance by 1 °C.

Specific heat is a property that is specific to a given type of matter, and substances vary in their specific heat. Metals tend to have low specific heat. Water has very high specific heat.

Vocabulary

specific heat: Amount of energy (in joules) needed to raise the temperature of 1 kilogram of a substance by 1 °C.